CARBONIFEROUS PERIOD ~ 358.9–298.9 million years ago

CARBONIFEROUS PERIOD


Terrestrial life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would eventually evolve into reptiles, the first fully terrestrial vertebrates. Arthropods were also very common, and many (such as Meganeura), were much larger than those of today. Vast swaths of forest covered the land, which would eventually be laid down and become the coal beds characteristic of the Carboniferous system. A minor marine and terrestrial extinction event occurred in the middle of the period, caused by a change in climate. The latter half of the period experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea.

Early Carboniferous land plants, some of which were preserved in coal balls, were very similar to those of the preceding Late Devonian, but new groups also appeared at this time.

The main Early Carboniferous plants were the Equisetales (horse-tails), Sphenophyllales (vine-like plants), Lycopodiales (club mosses), Lepidodendrales (scale trees), Filicales (ferns), Medullosales (informally included in the "seed ferns", an artificial assemblage of a number of early gymnosperm groups) and the Cordaitales. These continued to dominate throughout the period, but during late Carboniferous, several other groups, Cycadophyta (cycads), the Callistophytales (another group of "seed ferns"), and the Voltziales (related to and sometimes included under the conifers), appeared.

The Carboniferous lycophytes of the order Lepidodendrales, which are cousins (but not ancestors) of the tiny club-moss of today, were huge trees with trunks 30 meters high and up to 1.5 meters in diameter. These included Lepidodendron (with its fruit cone called Lepidostrobus), Halonia, Lepidophloios and Sigillaria. The roots of several of these forms are known as Stigmaria. Unlike present day trees, their secondary growth took place in the cortex, which also provided stability, instead of the xylem. The Cladoxylopsids were large trees, that were ancestors of ferns, first arising in the Carboniferous.

The fronds of some Carboniferous ferns are almost identical with those of living species. Probably many species were epiphytic. Fossil ferns and "seed ferns" include Pecopteris, Cyclopteris, Neuropteris, Alethopteris, and Sphenopteris; Megaphyton and Caulopteris were tree ferns.

The Equisetales included the common giant form Calamites, with a trunk diameter of 30 to 60 cm (24 in) and a height of up to 20 m (66 ft). Sphenophyllum was a slender climbing plant with whorls of leaves, which was probably related both to the calamites and the lycopods.


Cordaites, a tall plant (6 to over 30 meters) with strap-like leaves, was related to the cycads and conifers; the catkin-like inflorescence, which bore yew-like berries, is called Cardiocarpus. These plants were thought to live in swamps and mangroves. True coniferous trees (Walchia, of the order Voltziales) appear later in the Carboniferous, and preferred higher drier ground.



SUPPLEMENT FROM THE ENCYCLOPEDIA BRITANNICA
PUBLISHED 1824


Calamites 'Horsetail'




Calamites is a genus of extinct arborescent (tree-like) horsetails to which the modern horsetails (genus Equisetum) are closely related. Unlike their herbaceous modern cousins, these plants were medium-sized trees, growing to heights of more than 30 meters (100 feet). They were components of the understories of coal swamps of the Carboniferous Period (around 360 to 300 million years ago).

Cordaites Tree


Cordaites is an important genus of extinct gymnosperms which grew on wet ground similar to the Everglades in Florida. Brackish water mussels and crustacea are found frequently between the roots of these trees. The fossils are found in rock sections from the Upper Carboniferous (323 to 299 million years ago) of the Dutch - Belgian - German coal area. A number of many noteworthy types from this line are: Cordaites principalis, Cordaites ludlowi (named after Ludlow, a coal area in England), Cordaites hislopii, found in Paleorrota geopark in Brazil, in contrast to many other plant varieties, Cordaites seeds are not rare, because they are rather large (up to 10 mm); those seeds are named Cordaicarpus.

In 1997 a fossil tree was found in an open-cast coal mine at Great Lumley. Parts of this "Cordaites" tree are on display in the Durham Botanic Gardens and at Great Lumley Millennium Park

These fossil trees have been examined by Professor Andrew Scott of London University, who reports that they are examples of an ancestor of modern fir trees (conifers). Logs of this type with similar carbonate mineralisation, have been found elsewhere in the world, but not previously in Britain. They are called Cordaites, a name used for extinct seed-bearing plants related to the conifers, Cordaites was a tall tree, up to 30 meters high, that had narrow strap-like leaves about one meter long. Although the long stems have not previously been found in Britain, leaves and branches are common fossils in the Coal Measures. The occurrence of mineralised tree trunks at Priors Close and not at other Coal Measures in Britain needs explanation.

Durham Botanic Gardens

Great Lumley Millennium Park 



Cordaites Tree - Leafs #1 [Nose Point, Seaham, Co. Durham]

Cordaites Tree - Leaf Close Up #1 [Nose Point, Seaham, Co. Durham]



Sigillaria Tree

Stigmaria: This fossil tree is one of the earliest trees, a Sigillaria, from the carboniferous period 320 million years ago.

Sigillaria tree from Stanhope, County Durham, UK

The tree was found in a stone quarry near Edmundbyers Cross in 1915 and brought to the churchyard, where it is a prominent feature of the town centre.



Lonchopteris

Lonchopteris eschweileriana


Specimen:            [Rare] Lonchopteris eschweileriana
Locality:            Poland, GZW - Upper Silesia Coal Basin
Stratigraphy:        Westfal B - "Orzeskie" Beds
Age:                 circa 305 million years
Dimensions:          9, 0 x 4, 0 x 0, 5 cm [fern 6, 0 cm long]

Seed ferns (Pteridosperms) like Lonchopteris were group of seed plants from the Carboniferous and Permian periods (about 360 to 250 million years ago). Some, such as Medullosa ( Lonchopteris, Neuropteris, Alethopteris etc.) grew as upright, unbranched woody trunks topped with a crown of large fernlike fronds; others, such as Mariopterids, were woody vines.

All had fernlike foliage; however, they reproduced by seeds, with ovules and pollen organs attached to the fronds. Gamete - producing structures in the seeds were surrounded by a hard inner integument and a fleshy outer layer. These features have led some authorities to speculate that these seeds may have been dispersed by animals. Some seeds were large. ( Pachytesta gigantea, a seed of Medullosa, grew up to 7 cm long.) Pollen organs of seed ferns were also large and complex and were commonly made up of many pollen sacs fused into a large structure.






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